Host responses to the HIV are complicated by circulating T cell membrane components such as IL-2R which can interfere with T cell growth and activation signals. Other T cell membrane components such as CD4 can complex to viral envelope proteins, as gp160, along with anti 160 antibody form large complexes. Clinical trials of human growth hormone in normal non-HIV infected individuals have not shown any effects on immune function or granulocyte function. This may be due to the relatively short period of the trials.